Tumor Biology: An Introduction

Abstract

About 200 different types of cells and their coordination make up and run the human body. And each of these cells is governed by the genetic information encoded in the DNA present in the cells’ nuclei. Although the nucleotide sequence of DNA is well checked and maintained throughout one’s life, mutations still occur that in certain instances cause diseases, cancer being one of them. The failure of the intricate genetic system that balances cell birth and cell death causes cancer. Cancer cells are clonal as a single common ancestral cell gradually accumulates mutation to form a tumor that over time develops malignancy. Growth factors are important components of tumor microenvironment that provide heterogeneity and autonomy to cancer cells, the properties that normal cells lack. Not only spontaneous mutations and genetic predisposition but also lifestyle, to a great extent, contributes to carcinogenesis. Tobacco smoke, UV rays, X-rays, agents that attack DNA, and change in its chemical structure are potential carcinogens. Viruses too can cause carcinogenesis. Whatever be the causes, they all affect the fundamental aspects of cellular function, including DNA repair, cell cycle regulation, apoptosis, and signal transduction. Thus, correct and effective management of this fatal disease is only possible if the underlying biological complicacies are well understood.

The gene that enables birds to learn songs can become cancer-causing. There is no normal physiological process that can’t be bastardized by the disease.

Siddhartha Mukherjee (Oncologist and Author)